High-Performance All-Polymer Solar Cells with a High Fill Factor and a Broad Tolerance to the Donor/Acceptor Ratio

Abstract

Manipulating the donor/acceptor (D/A) weight ratio is a critical route to produce highly efficient polymer solar cells (PSCs). However, most of the reported device performances are strongly sensitive to the blend ratio. In this work, highly efficient all-PSCs based on PBDB-T:N2200 active layer have been achieved, presenting impressive photovoltaic performance with high tolerance to wide D/A ratios ranging from 1:1 to 9:1, thus providing a broad blend ratio processing window for future practical production. In particular, the optimal device delivers the champion power conversion efficiency (PCE) of 8.61% with an outstanding fill factor (FF) of up to 75.4%, which is one of the highest FF values for the reported binary all-PSCs. Comprehensive morphological, electrical, and mechanism analysis together pointed out that the remarkable device performance are derived from the favorable interpenetrating network morphology, efficient exciton generation/dissociation, well-balanced carrier transport, and reduced bimolecular recombination. Moreover, compared to the small molecule-based and fullerene-based PSC counterparts, the all-PSCs demonstrate an excellent resilience to the D/A ratio, maintaining over 50% of the maximum PCE at a ratio of 49:1 with an extremely low acceptor content. These results depict a bright prospect of the developed all-PSCs for promising applications as flexible and scalable optoelectronic devices.

10.13% Efficiency All‐Polymer Solar Cells Enabled by Improving the Optical Absorption of Polymer Acceptors

“…Regarding such SM acceptor‐based PSCs, the all‐polymer solar cells (all‐PSCs) consisting of a polymer donor and a polymer acceptor show unique advantages in the flexible large‐scale and wearable energy generators due to their excellent morphology stability and mechanical robustness . However, most of the efficient all‐PSCs have PCEs ranging in 8–10%, although a few of them achieved PCEs over 11%, which is still far behind that of the efficient PSCs based on SM acceptors due to the lack of high‐performance polymer acceptors. To date, polymer acceptors have been mainly confined into a small number of structural building blocks, and the most widely studied one is the polymer N2200 with a donor–acceptor (D–A) backbone of naphthalene diimide (NDI)‐ alt ‐bithiophene due to its NBG and suitable molecular energy levels .…”

Simultaneously Improved Efficiency and Stability in All-Polymer Solar Cells by a P–i–N Architecture

“…Quite recently, through adopting a modified conventional device structure, Yang et al reported the efficient PBDB-T:N2200 BHJ device with a best PCE of 8.61%. [43] Fortunately, the strategy of P-i-N structure can take full advantages of both improved absorption and carrier transport in highly-crystalline pure N2200 phase. After optimization (see Table S1-S4, SI), a significantly enhanced average Jsc of 14.79 mA/cm 2 , slightly improved Voc of 0.898 V and FF of 66.3 % is observed, giving a remarkably improved average PCE of 9.28 % and the best one of 9.52%.…”

Spatial Distribution Recast for Organic Bulk Heterojunctions for High‐Performance All‐Inorganic Perovskite/Organic Integrated Solar Cells

“…As expected, the BHJ-2-RC-based OSC exhibits poor performance compared with BHJ-2-based OSC due to the insufficient exciton generation and dissociation stemming from the acceptor-scarcity film. [48] However, the improved hole transporting capability of BHJ-2-RC can further balance the hole and electron mobilities of ISC, which not only contributes to an additional 20% of J sc but also reduces charge carrier recombination, thus giving a high FF in the ISC.…”